Patent GB-745180-A (GB)
Title: Improvements in or relating to cathode ray tubes
IPC: H04N9/26
Filed: 1953-08-06
Abstract: 745,180. Cathode-ray tubes. CHROMATIC TELEVISION LABORATORIES, Inc. Aug. 6, 1953 [Sept. 2, 1952], No. 21677/53. Class 39 (1). A target structure of a cathode-ray tube comprises a light-transmitting imperforate baseplate 33, Fig. 3, carrying target area 66 and having spacers 43, 45 on one face thereof, and conductive strands 51 passing over spacers 43, 45 and secured at their ends to the opposite face of base plate 33. The target comprises translucent borosilicate glass plate 33 carrying three colour phosphor strips 66 and metal wires 51 passing over spacers 43, 45 and channel-shaped metal members 35, 37 fitting over opposed edges of plate 33 and anchored at their ends by ceramic cement 65, 67. Rectangular pieces of glass ribbon or mica 39, 41 are interposed between members 35, 37 and the wires 51 and may or may not be cemented to members 35, 37 by vitreous cement. Spacers 43, 45 are cemented to plate 33, this cement comprising potassium silicate with or without glass frit. The spacers, which may also be of borosilicate glass, have slots along their length formed by abrasive or photo-etching processes to hold wires 51. The spacing of the slots may be graduated to compensate for the different angles of incidence of the beam. In manufacture, stainless steel or nickel wire 51 is wound (under tension) continuously around the target assembly, in alternate channels of spacers 43, 45 and in contact with terminal 55, which may or may not be cemented with ceramic cement to member 39. Insulating spacers 57, 59 which may be of the same material of 39, 41 and terminal 61 are then placed in position and the intermediate wires 51 wound over 57, 59, 61 and in the intermediate channels of 43, 45. The two sets of wires are thus insulated from one another and can be used for colour switching. After winding a layer of ceramic cement 65, 67 is brushed or dabbed on to wires 51 and baked to set it, and the wire portions between 65, 67 are removed. An aluminium film can be sputtered on to phosphors 66. If the cathode-wire grid potential is one quarter of the cathode-screen potential, the grid wires bring the beam to a line focus on a given phosphor strip. The beam may be blanked during the transistion between two colours. The target structure is insulatedly supported from the metal envelope by insulated rivets or bolts which attach members 35, 37 or extensions thereof to angle pieces welded to the envelope. In a modification, Fig. 8, alternate wires have common terminal 71 and intermediate wires a similar common terminal at the other edge of 33<SP>1</SP>. The wire ends not connected to terminals are depressed out of the plane of the connected ends. The connections are effected by soldering or welding. The saddle members are of a steel alloy comprising 18.5 per cent chromium, 0.08 per cent carbon, 0.49 per cent manganese, 0.02 per cent phosphorus, 0.01 per cent sulphur, 0.62 per cent titanium, 0.20 per cent nickel, 0.4 per cent aluminium, 0.29 per cent silicon and the balance iron. There may be only two colours of response and the screen may have colour filters. There may be one. or more electron beams. Specification 745,181 is referred to.